Carbon-coated aluminum and method for producing same

ABSTRACT

Provided are an aluminum material coated with carbon which can improve the adhesion between an aluminum material and an active substance layer, and a manufacturing method thereof. The aluminum material coated with carbon includes an aluminum material ( 1 ) and a carbon-containing layer ( 2 ) formed on the surface of the aluminum material ( 1 ), and also includes an interposition layer ( 3 ) that is formed between the aluminum material ( 1 ) and the carbon-containing layer ( 2 ) and contains an aluminum element and a carbon element. The manufacturing method of an aluminum material coated with carbon includes a step of arranging an aluminum material in a space containing a hydrocarbon-containing substance and a step of heating in the state where the aluminum material is arranged in the space containing the hydrocarbon-containing substance.

TECHNICAL FIELD

This invention relates to an aluminum material coated with carbon, anelectrode structure, a capacitor or a battery using the aluminummaterial coated with carbon, and a manufacturing method of the aluminummaterial coated with carbon. More particularly, this invention relatesto an aluminum foil coated with carbon as an electrode material or anelectrode current collector material used for a lithium battery, lithiumion battery, lithium ion polymer battery, dye-sensitive solar battery,electric double-layer capacitor, electrolytic capacitor and the like, analuminum plate coated with carbon as an electrode material or anelectrode current collector material used for a fuel cell, solid polymerfuel cell and the like, and a manufacturing method thereof.

BACKGROUND ART

There are batteries as measures taken to convert chemical energydirectly to electric energy. These batteries have the ability todischarge an electric charge or to charge and discharge an electriccharge repeatedly with the use of electrochemical change and aretherefore used as power sources of various electric or electronicdevices. Also, there are capacitors as devices having the ability tocharge and discharge an electric charge repeatedly and these capacitorsare used as electric element parts of various electric or electronicdevices.

Lithium ion batteries and lithium ion polymer batteries, which aresecondary batteries having high energy efficiency, are currently used aspower sources for portable telephones, personal computers and cameras.Also, a trial is made to use a fuel cell as a power source forautomobiles. As to solar batteries, dye-sensitive solar batteries whichare low cost and common types are being developed as crystal-type,amorphous-type or thin film-type solar batteries in the next generation.

In fuel cells, for example, a material obtained by coating the surfaceof a current collector made of an aluminum plate is coated with anactive substance constituted of a carbon material is used as a cathodematerial.

In the dye-sensitive solar batteries, a material obtained by coating thesurface of a thin-film substrate with a conductive material such ascarbon materials is used as an electrode material.

In an electric double layer capacitor which is one of electrochemicalcapacitors, on the other hand, a material obtained by coating thesurface of a current collector made of an aluminum foil with an activesubstance made of an active carbon powder is used as a polar electrode.Specifically, a binder material, a conductive agent and the like areadded to and mixed with an activated carbon powder to prepare a slurrylike material, which is then applied to the surface of the aluminum foiland then dried at ambient temperature and the dried material is cut intoa predetermined size to manufacture a polar electrode. There is also thecase where a polar electrode is manufactured by applying a mixture of anactivated carbon powder, a resin and the like onto the surface of analuminum foil under pressure and heating.

In an electrolytic capacitor, conventionally, a conductor made of analuminum foil having a surface area enlarged by etching has been usedfor a cathode material. However, capacitors in which the surface of theelectrode is enlarged by adhering a carbon powder onto the surface of analuminum foil have been developed in recent years.

As a method of manufacturing an aluminum material coated with carbonwhich is to be used for electrode material such as batteries andcapacitors, a method in which a carbon intermediate film or anintermediate film of a metal richer than aluminum is provided on analuminum current collector and an active substance layer such as carbonis applied to the intermediate film is disclosed in Japanese UnexaminedPatent Publication No. 2000-164466. Also, WO 00/07253 discloses acurrent collector used to fabricate a lithium secondary battery, whichis increased in surface area, improved in binding strength with anactive substance layer and has excellent charging/dischargingcharacteristics by treating an aluminum material and a copper currentcollector used as a current collector in a lithium secondary battery asan aqueous acidic solution, aqueous basic solution or aqueous neutralsolution and, in some cases, forming a conductive polymer film.

However, even if any of the above methods is used, the resultingaluminum material coated with carbon is inferior in adhesion between theactive substance layer made of a carbon-containing material and thesurface of an aluminum material. For this, there is the case where theactive substance layer is separated from the surface of an aluminummaterial when a secondary battery or a capacitor is charged ordischarged. As a result, there arises a problem that, for example, thecharging/discharging characteristics and life of a secondary battery ora capacitor are dropped.

In order to obtain, for example, an electric double layer capacitorhaving a large capacity, it is necessary to increase the contact areabetween a polar electrode and an electrolytic solution by forming athick active substance layer on the surface of a current collector.However, if a conventional aluminum material coated with carbon is usedto constitute an electrode, this poses a problem that the activesubstance layer comprising carbon-containing substance is separated fromthe current collector made of an aluminum material when the capacitor ischarged or discharged.

DISCLOSURE OF THE INVENTION

Thus, it is an object of this invention to solve the above problems andto provide a structure of an aluminum material coated with carbon thatcan improve the adhesion between an aluminum material and an activesubstance layer and a manufacturing method thereof.

It is another object of this invention to provide an electrode structuremade of an aluminum material coated with carbon that can improve theadhesion between an aluminum material and an active substance layer.

It is still another object of this invention to provide a capacitorprovided with an electrode structure made of an aluminum material coatedwith carbon that can improve the adhesion between an aluminum materialand an active substance layer.

It is yet another object of this invention to provide a battery providedwith an electrode structure made of an aluminum material coated withcarbon that can improve the adhesion between an aluminum material and anactive substance layer.

The inventors of this invention have made earnest studies to solve theproblems about the conventional art and, as a result, have found that analuminum material coated with carbon, that can attain the above object,can be obtained by heating an aluminum material in a specific condition.This invention was made based on the findings of the inventors.

An aluminum material coated with carbon according to this inventionincludes an aluminum material and a carbon-containing layer formed onthe surface of the aluminum material, and also includes an interpositionlayer that is formed between the aluminum material and thecarbon-containing layer and contains an aluminum element and a carbonelement.

In this aluminum material coated with carbon, the interposition layerformed between the aluminum material and the carbon-containing layer asan active substance layer exhibits the effect of improving the adhesionbetween the aluminum material and the active substance layer. Also, thecarbon-containing layer exhibits the effect of enlarging or increasingthe surface area of the aluminum material. Therefore, the interpositionlayer exhibits the effect of improving the adhesion between thecarbon-containing layer which is an active substance layer thatincreases the surface area of the aluminum material and the aluminummaterial. An improvement in adhesion to the active substance layer andan increase in surface area can be attained in the aluminum materialcoated with carbon.

In the aluminum material coated with carbon according to this invention,preferably, the carbon-containing layer includes therein aninterposition material containing an aluminum element and a carbonelement.

When the carbon-containing layer is thin, the adhesion between thealuminum material and the active substance layer can be more improvedrather than that of a conventional one by only making the aboveinterposition layer present. However, when the carbon-containing layeris thick, there is a possibility of separation in the interior thereof.In this case, the adhesion inside the carbon-containing layer can beraised and it is therefore possible to prevent separation by forming aninterposition material containing an aluminum element and a carbonelement inside the carbon-containing layer.

The interposition material is preferably a compound of an aluminumelement and a carbon element. Also, the carbon-containing layer ispreferably a compound of an aluminum element and a carbon element.

In the aluminum material coated with carbon according to this invention,preferably, the carbon-containing layer is formed so as to extendoutward from the surface of the aluminum material. In this case, thecarbon-containing layer exhibits the effect of enlarging or increasingthe surface area of the aluminum material more effectively.

In the aluminum material coated with carbon according to this invention,preferably, the interposition layer constitutes a first surface portionthat is formed on at least a part of the surface of the aluminummaterial and contains a carbide of aluminum. The carbon-containing layerpreferably constitutes a second surface portion that is formed so as toextend outward from the first surface portion.

In this case, the second surface portion exhibits the effect ofincreasing the surface area of the aluminum material. Also, since thefirst surface portion containing a carbide of aluminum is formed betweenthe aluminum material and the second surface portion, this first portionexhibits the effect of increasing the adhesion to the second surfaceportion that increases the surface area of the aluminum material. Animprovement in adhesion to the active substance layer and an increase insurface area can be thereby made more effectively in the aluminummaterial coated with carbon.

Also, it is preferable that the carbon-containing layer further includescarbon particles, and the second surface portion is formed between thefirst surface portion and the carbon particles and contains a carbide ofaluminum. In this case, even if a thick carbon-containing layer isformed, the adhesion between the carbon-containing layer as an activesubstance layer and an aluminum material can be surely kept.

Preferably, the carbon-containing layer includes aluminum particles inaddition to the carbon particles, and also includes an aluminum particlesurface portion that is formed on at least a part of the surface of thealuminum particles and contains a carbide of aluminum and an aluminumparticle outside portion that is formed so as to extend outward thesurface of the aluminum particles from the aluminum particle surfaceportion and contains a carbide of aluminum. In this case, even if athicker carbon-containing layer is formed, the adhesion in thecarbon-containing layer as an active substance layer can be raised andthis can prevent separation.

The carbon-containing layer includes aluminum particles in place ofcarbon particles, and also includes an aluminum particle surface portionthat is formed on at least a part of the surface of the aluminumparticles and contains a carbide of aluminum and an aluminum particleoutside portion that is formed so as to extend outward the surface ofthe aluminum particles from the aluminum particle surface portion andcontains a carbide of aluminum. The second surface portion may be formedbetween the first surface portion and the aluminum particles and maycontain a carbide of aluminum. In this case, a carbon-containing layerhaving a large surface area per unit projected area as the activesubstance layer can be formed.

In the aluminum material coated with carbon according to this invention,preferably, a ratio of in thickness of the carbon-containing layer iswithin a range between 0.1 or more and 1000 or less with respect to athickness of the aluminum material.

The aluminum material coated with carbon which has any one of theaforementioned characteristics is used to constitute an electrodestructure. The electrode structure is preferably an electrode or anelectrode current collector.

The above electrode structure is used to constitute a capacitor. Theelectrode structure can improve, for example, the charging/dischargingcharacteristics and life of the capacitor. The capacitor is preferablyeither an electrochemical capacitor or an electrolytic capacitor.

Also, the above electrode structure is used to constitute a battery.This electrode structure can improve the charging/dischargingcharacteristics and life of the battery.

A manufacturing method of an aluminum material coated with carbonaccording to this invention includes a step of arranging an aluminummaterial in a space containing a hydrocarbon-containing substance and astep of heating in the state where the aluminum material is arranged inthe space containing the hydrocarbon-containing substance.

In the manufacturing method according to this invention, unlike aconventional method, it is necessary neither to provide an intermediatefilm nor to carry out pretreatment or it is unnecessary to carry out aseries of processes such as drying and pressure bonding after applyingthe carbon-containing layer to secure the adhesion. Not only the surfaceof an aluminum material can be coated with an active substance layerincluding a carbon-containing layer but also an interposition layercontaining an aluminum element and a carbon element can be formedbetween the aluminum material and the active substance layer by a simpleprocess in which an aluminum material is arranged in a space containinga hydrocarbon-containing substance and heated. This structure makes itpossible to improve the adhesion between the aluminum material and thecarbon-containing layer as an active substance layer.

Also, the manufacturing method of an aluminum material according to thepresent invention may further includes a step of cooling and reheatingthe aluminum material after the step of heating in the state where thealuminum material is arranged in the space containing thehydrocarbon-containing substance, namely, an activating step.

In this case, the step of cooling and reheating the aluminum material ispreferably carried out within a temperature range between 100° C. ormore and less than 660° C.

In the manufacturing method of an aluminum material according to thisinvention, preferably, the step of arranging the aluminum material inthe space containing the hydrocarbon-containing substance involvesadhering at least one kind selected from the group consisting of acarbon-containing substance and an aluminum powder to the surface of thealuminum material and, then, arranging the aluminum material in thespace containing the hydrocarbon-containing substance.

Specifically, in the step of arranging the aluminum material of themanufacturing method according to this invention, an aluminum materialmay be arranged in a space containing a hydrocarbon-containing substanceafter a carbon-containing substance is adhered to the surface of thealuminum material, an aluminum material may be arranged in a spacecontaining a hydrocarbon-containing substance after an aluminum powderis adhered to the surface of the aluminum material or an aluminummaterial may be arranged in a space containing a hydrocarbon-containingsubstance after a carbon-containing substance and an aluminum powder areadhered to the surface of the aluminum material.

In the case of forming a thin carbon-containing layer, the adhesionbetween the aluminum foil and the active substance layer can be moreimproved than the case of a conventional one only in the presence of theabove interposition layer only by arranging an aluminum material in aspace containing a hydrocarbon-containing substance and heating.However, in the case of forming a thick carbon-containing layer, analuminum material is preferably arranged in a space containing ahydrocarbon-containing substance after the carbon-containing substanceis adhered to the surface of the aluminum material to heat thecarbon-containing layer to keep the adhesion between the aluminummaterial and the active substance layer without fail.

When a thicker carbon-containing layer is formed, there is thepossibility of separation occurs at the interior of thecarbon-containing layer. In this case, after a carbon-containingsubstance and an aluminum powder are adhered to the surface of thealuminum material, the aluminum material is arranged in a spacecontaining a hydrocarbon-containing substance, followed by heating toform an interposition material containing an aluminum element and acarbon element inside the carbon-containing layer, so that adhesioninside the carbon-containing layer can be raised and separation can bethereby prevented.

Moreover, in order to form the active substance layer having a largesurface area per unit projected area, the aluminum material ispreferably arranged in a space containing a hydrocarbon-containingsubstance, followed by heating, after an aluminum powder is adhered tothe surface of the aluminum material. Alternatively, after the surfaceof the aluminum material is roughened, the aluminum material may bearranged in a space containing a hydrocarbon-containing substance andheated.

It is to be noted that when at least one kind selected from the groupconsisting of a carbon-containing substance and an aluminum powder isadhered to the surface of the aluminum material in the manufacturingmethod according to this invention, a binder may be used. The binder ispreferably an organic polymer type that can be burned when heated.

In the manufacturing method according to this invention, the step ofheating the aluminum material is preferably carried out within atemperature range between 450° C. or more and less than 660° C.

Also, in the manufacturing method according to this invention, thealuminum material is preferably arranged in a space containing aparaffin-type hydrocarbon or methane in the step of arranging thealuminum material in the space containing the hydrocarbongroup-containing material.

As mentioned above, the aluminum material coated with carbon accordingto this invention ensures that the adhesion between thecarbon-containing layer and the aluminum material can be more improvedthan a conventional case. Also, if an electrode structure is constitutedby using the aluminum material coated with carbon according to thisinvention, for example, the charging/discharging characteristics andlife of a battery or a capacitor can be improved. Furthermore, with themanufacturing method of an aluminum material coated with carbonaccording to this invention, not only the surface of the aluminummaterial can be coated with an active substance layer including acarbon-containing layer but also an interposition layer containing analuminum element and a carbon element can be formed between the aluminummaterial and the active substance layer, whereby the adhesion betweenthe carbon-containing layer and the aluminum material can be moreimproved than that of a conventional one by a simple process in whichthe aluminum material is arranged in a space containing ahydrocarbon-containing substance, followed by heating.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a typical view showing a sectional structure of an aluminummaterial coated with carbon as one embodiment of this invention.

FIG. 2 is a typical view showing a sectional structure of an aluminummaterial coated with carbon as another embodiment of this invention.

FIG. 3 is a typical view showing a sectional structure of an aluminummaterial coated with carbon as still another embodiment of thisinvention.

FIG. 4 is a typical view showing a sectional structure of an aluminummaterial coated with carbon as a yet another embodiment of thisinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

According to the sectional structure of an aluminum material coated withcarbon as one embodiment of this invention as shown in FIG. 1, acarbon-containing layer 2 is formed on the surface of an aluminummaterial (an aluminum plate or an aluminum foil) 1. An interpositionlayer 3 containing an aluminum element and a carbon element is formedbetween the aluminum material 1 and the carbon-containing layer 2. Thecarbon-containing layer 2 is formed so as to extend outward from thesurface of the aluminum material 1. The interposition layer 3constitutes a first surface portion that is formed on at least a part ofthe surface of the aluminum material 1 and contains a carbide ofaluminum. The carbon-containing layer 2 includes a second surfaceportion 21 that is formed so as to extend in a fibrous form or afilament form outward from the first surface portion 3. The secondsurface portion 21 is a compound of an aluminum element and a carbonelement.

Also, as shown in FIG. 2, the sectional structure of the aluminummaterial coated with carbon as another embodiment of this invention hasalmost the same structure as the sectional structure shown in FIG. 1,wherein the carbon-containing layer 2 further includes a large number ofcarbon particles 22. The second surface portion 21 extends outward in afibrous form or a filament form from the first surface portion 3, isformed between the first surface portion 3 and the carbon particles 22and contains a carbide of aluminum.

Moreover, as shown in FIG. 3, the sectional structure of an aluminummaterial coated with carbon as still another embodiment of thisinvention has almost the same structure as the sectional structure shownin FIG. 1, wherein the carbon-containing layer 2 further includes alarge number of aluminum particles 23. An aluminum particle surfaceportion 24 is formed on at least a part of the surface of the aluminumparticles 23 and contains a carbide of aluminum. An aluminum particleoutside portion 25 is formed so as to extend in a cactus form outwardthe surface of the aluminum particles 23 from the aluminum particlesurface portion 24 and contains a carbide of aluminum. The secondsurface portion 21 extends in a fibrous form or a filament form outwardfrom the first surface portion 3, is formed between the first surfaceportion 3 and the aluminum particles 23 and contains a carbide ofaluminum.

Also, as shown in FIG. 4, the sectional structure of the aluminummaterial coated with carbon as yet another embodiment of this inventionhas almost the same structure as the sectional structure shown in FIG.1, wherein the carbon-containing layer 2 further includes a large numberof carbon particles 22 and a large number of aluminum particles 23. Thesecond surface portion 21 extends in a fibrous form or a filament formoutward from the first surface portion 3, is formed between the firstsurface portion 3 and the carbon particles 22 and contains a carbide ofaluminum. Moreover, an aluminum particle surface portion 24 is formed onat least a part of the surface of the aluminum particles 23 and containsa carbide of aluminum. An aluminum particle outside portion 25 is formedso as to extend in a cactus form outward the surface of the aluminumparticles 23 from the aluminum particle surface portion 24 and containsa carbide of aluminum.

In one embodiment of this invention, no particular limitation is imposedon the type of aluminum material as a base material on which thecarbon-containing layer is to be formed. As the aluminum material, purealuminum or an aluminum alloy may be used. Such an aluminum material ispreferably those having an aluminum purity of 98% by mass or more as avalue measured according to the method described in “JIS H2111”. Thealuminum foil used in the present invention has compositions includingaluminum alloys prepared by adding at least one alloy element among lead(Pb), silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium(Mg), chromium (Cr), zinc (Zn), titanium (Ti), vanadium (V), gallium(Ga), nickel (Ni) and boron (B) in an amount considered to be necessary,and aluminum limited in the amount of the above unavoidable impurityelements. Although no particular limitation is imposed on the thicknessof the aluminum material, the thickness is preferably within a rangebetween 5 μm or more and 200 μm or less in the case of a foil and in arange from 200 μm to 3 mm in the case of a plate.

As the above aluminum material, those manufactured by known methods maybe used. For example, a molten bath of aluminum or an aluminum alloyhaving the above predetermined composition is prepared and cast toobtain an ingot, which is then homogenized properly. After that, thisingot is subjected to hot rolling and cold rolling to be able to obtainan aluminum material. In this case, the above ingot may be subjected tointermediate annealing treatment within a temperature range between 150°C. or more and 400° C. or less during the course of the above coldrolling step.

The aluminum material coated with carbon according to this invention isoptimal for use as a gas electrode material of a fuel cell, a polarelectrode material of an electric double layer capacitor and a cathodematerial of an electrolytic capacitor.

In the meantime, a material prepared by forming an active substancelayer on the surface of an aluminum material used as a current collectorlayer has been used as a positive electrode material of lithium ion typesecondary batteries such as a lithium ion battery and lithium ionpolymer battery. As a negative electrode material, a material preparedby forming an active substance layer including a carbon-containing layeron a copper foil used as a current collector has been used. The aluminummaterial coated with carbon according to the present invention is alsoeffective when it is used a current collector material to improve theadhesion of an electrode material (a mixture of metal acid lithium,carbon, a binder and the like) that is applied to the surface of acurrent collector in a positive electrode material of the above lithiumion type secondary batteries. In order to lighten these secondarybatteries, an attempt has been made to use an aluminum material as acurrent collector in a negative electrode material. The aluminummaterial coated with carbon according to this invention is optimal foruse as a negative electrode material of a lithium ion type secondarybattery corresponding to such an attempt.

In one embodiment of the manufacturing method of an aluminum materialcoated with carbon according to this invention, no particular limitationis imposed on the kind of hydrocarbon-containing substance to be used.Examples of the kind of hydrocarbon-containing substance includeparaffin-type hydrocarbons such as methane, ethane, propane, n-butane,isobutane and pentane, olefin-type hydrocarbons such as ethylene,propylene, butene and butadiene, acetylene-type hydrocarbons such asacetylene or derivatives of these hydrocarbons. Among thesehydrocarbons, paraffin-type hydrocarbons such as methane, ethane andpropane are gasified in the step of heating the aluminum foil and aretherefore preferable. Any one of hydrocarbons such as methane, ethaneand propane is more preferable. Methane in the hydrocarbons is mostpreferable.

Also, the hydrocarbon-containing substance may be used in any of aliquid state and a gas state in the manufacturing method according tothis invention. It is only required for the hydrocarbon-containingsubstance to exist in a space where an aluminum material is present andany method may be used to introduce the hydrocarbon-containing substanceinto a space where an aluminum material is arranged. When thehydrocarbon-containing substance has a gas state (e.g., methane, ethaneor propane), it may be filled either singly or in combination with aninert gas in a sealed space where an aluminum material is subjected toheat treatment. Also, when the hydrocarbon-containing substance has aliquid state, it may be filled either singly or in combination withinert gas in a manner that it is gasified in a sealed space.

There is no particular limitation to the pressure in a heatingatmosphere in the step of heating an aluminum material and the heatingmay be carried out under normal pressure or reduced pressure or underpressure. Also, the pressure may be adjusted at any time when theatmosphere is kept at a constant temperature, when the atmosphere israised to a prescribed temperature and when the atmosphere is droppedfrom a prescribed temperature.

Although no particular limitation is imposed on the weight ratio of thehydrocarbon-containing substance to be introduced in a space where analuminum material is arranged, the weight ratio is preferably within arange between 0.1 parts by weight or more and 50 parts by weight orless, particularly preferably 0.5 parts by weight or more and 30 partsby weight or less, in terms of carbon with respect to 100 parts byweight of the aluminum material.

In the step of heating the aluminum material, the heating temperature ispreferably within a range between 450° C. or more and less than 660° C.,more preferably between 530° C. or more and 620° C. or less, though itmay be properly set in accordance with the composition of the aluminummaterial to be heated. However, the manufacturing method according tothis method does not exclude the case where the aluminum material isheated at a temperature less than 450° C. and it is only required forthe aluminum material to be heated at a temperature at least exceeding300° C.

The heating time is, though depending on, for example, heatingtemperature, generally within a range between 1 hour or more and 100hours or less.

When the heating temperature is 400° C. or more, the concentration ofoxygen in a heating atmosphere is preferably made to be 1.0% by volumeor less. When the heating temperature is 400° C. or more and theconcentration of oxygen in a heating atmosphere exceeds 1.0% by volume,a thermally oxidized film on the surface of the aluminum material ismade large and there is therefore a fear that the boundary electricresistance at the surface of the aluminum material is increased.

Also, the surface of the aluminum material may be roughened prior toheat treatment. There is no particular limitation to the surface rougingmethod and known techniques such as washing, etching and blasting may beused.

When a thick carbon-containing layer is formed in the manufacturingmethod according to this invention, a process is adopted in which aftera carbon-containing substance or a carbon-containing substance and analuminum powder are adhered to the surface of the aluminum material, thealuminum material is arranged in a space containing ahydrocarbon-containing layer and heated. In this case, as thecarbon-containing substance adhered to the surface of the aluminum foil,any of an active carbon fiber, active carbon cloth, active carbon felt,active carbon powder, Indian ink, carbon black and graphite may be used.As to the adhering method, the carbon-containing substance prepared inthe form of a slurry, a liquid or a solid by using a binder, a solventor water may be adhered onto the surface of the aluminum material byapplication, dipping or thermal and pressure bonding. After thecarbon-containing substance is adhered onto the surface of the aluminummaterial, it may be dried within a temperature range between 20° C. ormore and 300° C. or less.

In the case of adhering a carbon-containing substance and an aluminumpowder to the surface of the aluminum material to form a thickercarbon-containing layer in the manufacturing method according to thisinvention, the aluminum powder may be added at a weight ratio within arange between 0.01 parts by weight or more and 10000 parts by weight orless with respect to 100 parts by weight of the above carbon-containingsubstance.

EXAMPLES

Aluminum materials coated with carbon were fabricated in accordance withExamples 1 to 23 and Conventional Examples 1 to 3. For comparison withthe examples, reference examples of an aluminum material coated withcarbon were fabricated.

Examples 1 to 5

A carbon-containing substance was applied to both surfaces of analuminum hard foil having a thickness of 10 μm (JIS A1050-H18) and driedat 30° C. for 3 hours to adhere the carbon-containing substance to thefoil. The nominal purity of the aluminum foil was 99.55% by mass andmass analysis of the composition of the aluminum foil showed that theamounts of silicon and iron were 2250 ppm and 3800 ppm, respectively.The composition of the carbon-containing substance was as follows: 1part by weight of carbon black (trade name: #2400B, made by MitsubishiChemical Corporation) to which 6 parts by weight of isopropyl alcohol(IPA) and 3 parts by weight of 1,1,1 trichloroethane were added. Thecarbon-containing substance was adhered such that the dry thickness ofthe layer formed on one surface was 4 μm.

After that, the aluminum foil to which the carbon-containing substancewas adhered was heated for 12 hours in the atmospheric and temperaturecondition as shown in Table 1.

Example 6

A carbon-containing substance was applied to both surfaces of analuminum hard foil having a thickness of 10 μm (JIS A1050-H18) and driedat 100° C. for 10 minutes to adhere the carbon-containing substance tothe foil. The nominal purity of the aluminum foil was 99.55% by mass andmass analysis of the composition of the aluminum foil showed that theamounts of silicon and iron were 2250 ppm and 3800 ppm, respectively.The composition of the carbon-containing substance was as follows: 1part by weight of carbon black (trade name: #2400B, made by MitsubishiChemical Corporation) to which 1 part by weight of polyethyleneterephthalate (PET) was added. The carbon-containing substance wasadhered such that the dry thickness of the layer formed on one surfacewas 180 μm.

After that, the aluminum foil to which the carbon-containing substancewas adhered was heated for 12 hours in the atmospheric and temperaturecondition as shown in Table 1.

Example 7

A carbon-containing substance was adhered to both surfaces of analuminum hard foil in the same manner as in Example 6. Thereafter, thealuminum foil to which the carbon-containing substance was adhered wasrolled using a rolling mill at a reduction ratio of about 20% to bindthe carbon-containing substance to the surface of the aluminum foilunder pressure. The aluminum foil to which the carbon-containingsubstance was bound under pressure was heated for 12 hours in theatmospheric and temperature condition as shown in Table 1.

Example 8

A carbon-containing substance was applied to both surfaces of analuminum hard foil having a thickness of 10 μm (JIS A3003-H18) and driedat 100° C. for 10 minutes to adhere the carbon-containing substance tothe foil. The results of mass analysis of the composition of thealuminum foil were as follows: silicon: 0.57% by mass, iron: 0.62% bymass, copper: 0.1% by mass and manganese: 1.1% by mass. The compositionof the carbon-containing substance was as follows: 1 part by weight ofcarbon black (trade name: #2400B, made by Mitsubishi ChemicalCorporation) to which 1 part by weight of polyethylene terephthalate(PET) was added. The carbon-containing substance was adhered such thatthe dry thickness of the layer formed on one surface was 3 mm.

Thereafter, the aluminum foil to which the carbon-containing substancewas adhered was rolled using a rolling mill at a reduction ratio ofabout 30% to bind the carbon-containing substance to the surface of thealuminum foil under pressure. The aluminum foil to which thecarbon-containing substance was bound under pressure was heated for 12hours in the atmospheric and temperature condition as shown in Table 1.

Examples 9 to 12

A carbon-containing substance was applied to both surfaces of analuminum hard foil having a thickness of 10 μm (JIS A3003-H18) and driedat 100° C. for 10 minutes to adhere the carbon-containing substance tothe foil. The results of mass analysis of the composition of thealuminum foil were as follows: silicon: 0.57% by mass, iron: 0.62% bymass, copper: 0.1% by mass and manganese: 1.1% by mass. The compositionof the carbon-containing substance was as follows: 100 parts by weightof carbon black (trade name: #2400B, made by Mitsubishi ChemicalCorporation) to which 100 parts by weight of polyethylene terephthalate(PET) and an aluminum powder in the amount shown in Table 1 were added.The carbon-containing substance was adhered such that the dry thicknessof the layer formed on one surface was 3 mm.

Thereafter, the aluminum foil to which the carbon-containing substancewas adhered was rolled using a rolling mill at a reduction ratio ofabout 30% to bind the carbon-containing substance to the aluminum foilunder pressure. The aluminum foil to which the carbon-containingsubstance was bound under pressure was heated for 12 hours in theatmospheric and temperature condition as shown in Table 1.

Conventional Example 1

A carbon-containing substance was applied to both surfaces of analuminum hard foil having a thickness of 10 μm (JIS A1050-H18) and driedat 30° C. for 3 hours to adhere the carbon-containing substance to thefoil. The nominal purity of the aluminum foil was 99.55% by mass andmass analysis of the composition of the aluminum foil showed that theamounts of silicon and iron were 2250 ppm and 3800 ppm, respectively.The composition of the carbon-containing substance was as follows: 1part by weight of carbon black (trade name: #2400B, made by MitsubishiChemical Corporation) to which 6 parts by weight of isopropyl alcohol(IPA) and 3 parts by weight of 1,1,1 trichloroethane were added. Thecarbon-containing substance was adhered such that the dry thickness ofthe layer formed on one surface was 4 μm.

The aluminum foil coated with carbon which was obtained in this mannercorresponds to those which were not heat-treated in Examples 1 to 5.

Conventional Example 2

A carbon-containing substance was applied to both surfaces of analuminum hard foil having a thickness of 10 μm (JIS A1050-H18) and driedat 100° C. for 10 minutes to adhere the carbon-containing substance tothe foil. The nominal purity of the aluminum foil was 99.55% by mass andmass analysis of the composition of the aluminum foil showed that theamounts of silicon and iron were 2250 ppm and 3800 ppm, respectively.The composition of the carbon-containing substance was as follows: 1part by weight of carbon black (trade name: #2400B, made by MitsubishiChemical Corporation) to which 1 part by weight of polyethyleneterephthalate (PET) was added. The carbon-containing substance wasadhered such that the dry thickness of the layer formed on one surfacewas 180 μm.

The aluminum foil coated with carbon which was obtained in this mannercorresponds to one which was not heat-treated in Example 6.

Conventional Example 3

A carbon-containing substance was applied to both surfaces of analuminum hard foil having a thickness of 10 μm (JIS A3003-H18) and driedat 100° C. for 10 minutes to adhere the carbon-containing substance tothe foil. The results of mass analysis of the composition of thealuminum foil were as follows: silicon: 0.57% by mass, iron: 0.62% bymass, copper: 0.1% by mass and manganese: 1.1% by mass. The compositionof the carbon-containing substance was as follows: 1 part by weight ofcarbon black (trade name: #2400B, made by Mitsubishi ChemicalCorporation) to which 1 part by weight of polyethylene terephthalate(PET) was added. The carbon-containing substance was adhered such thatthe dry thickness of the layer formed on one surface was 3 mm.

The aluminum foil coated with carbon which was obtained in this mannercorresponds to one which was not heat-treated in Example 7.

Reference Example 1

A carbon-containing substance was applied to both surfaces of analuminum hard foil having a thickness of 10 μm (JIS A1050-H18) and driedat 30° C. for 3 hours to adhere the carbon-containing substance to thefoil. The nominal purity of the aluminum foil was 99.55% by mass andmass analysis of the composition of the aluminum foil showed that theamounts of silicon and iron were 2250 ppm and 3800 ppm, respectively.The composition of the carbon-containing substance was as follows: 1part by weight of carbon black (trade name: #2400B, made by MitsubishiChemical Corporation) to which 6 parts by weight of isopropyl alcohol(IPA) and 3 parts by weight of 1,1,1 trichloroethane were added. Thecarbon-containing substance was adhered such that the dry thickness ofthe layer formed on one surface was 4 μm.

After that, the aluminum foil to which the carbon-containing substancewas adhered was heated for 12 hours in the atmospheric and temperaturecondition as shown in Table 1.

With respect to the aluminum materials coated with carbon obtained inExamples 1 to 12, Conventional Examples 1 to 3 and Reference Example 1,evaluations were made for the adhesion between the carbon-containinglayer and the aluminum material, the formation amount of theinterposition layer containing an aluminum element and a carbon elementand the formation amount of interposition materials contained in thecarbon-containing layer. The evaluation conditions are as follows. Theevaluation results are shown in Table 1.

(Adhesion)

The adhesion was evaluated by a taping method. A pressure-sensitiveadhesive tape (trade name: “Scotch Tape”, made by Sumitomo 3M Ltd.)having a 15-mm-wide and 120-mm-long adhesive surface was pressed againstthe surface of a carbon-containing layer in a 10-mm-wide and 100-mm-longsample of the aluminum material coated with carbon and then theremovable adhesive tape was peeled off to evaluate the adhesionaccording to the following equation.

Adhesion (%)={weight (mg) of carbon-containing layer after peeled/weight(mg) of carbon-containing layer before peeled}×100 (Formation amounts ofinterposition layer and interposition material)

The formation amounts of the interposition layer and interpositionmaterials were evaluated by quantitative analysis of aluminum carbides.The gas generated by the sample of the aluminum material coated withcarbon was all dissolved in an aqueous 20% sodium hydroxide solution wascollected and quantitatively analyzed by using a high sensitivity gaschromatograph equipped with a flame ion detector and the detectedcontent was converted into the content of aluminum carbide (Al₄C₃).Based on this aluminum carbide content, the formation amounts of theinterposition layer and interposition materials were evaluated accordingto the following equation.

Formation amount of the interposition layer and interpositionmaterials=weight of aluminum carbides (Al₄C₃)/carbon-containing layer(mg). TABLE 1 Heating Formation amounts of Amount of Heating temperatureAdhesion interposition layer and aluminum powder atmosphere (° C.) (%)interposition material (parts by weight) Example 1 Acetylene gas 430 78540 — Example 2 Methane gas 470 82 1010 — Example 3 Methane gas 540 871350 — Example 4 Methane gas 580 93 8780 — Example 5 Methane gas 620 9813500 — Example 6 Methane gas 580 92 190 — Example 7 Methane gas 580 96210 — Example 8 Methane gas 580 77 12 — Example 9 Methane gas 580 82 130.05 Example 10 Methane gas 580 91 22 5 Example 11 Methane gas 580 97 48500 Example 12 Methane gas 580 93 600 50000 Conventional Example 1 — — 5Tr — Conventional Example 2 — — 10 Tr — Conventional Example 3 — — 3 Tr— Reference Example 1 Argon gas 580 6 Tr —

In Table 1, the term “Tr” shown in the column named “formation amountsof interposition layer and interposition material” shows that the amountare so small that it cannot be detected.

As is clear from the results of Table 1, the aluminum materials coatedwith carbon which were obtained in Examples 1 to 5 exhibitedconsiderably higher adhesion than the aluminum material of ConventionalExample 1. Also in the case of forming a thick carbon-containing layer,the aluminum materials coated with carbon which were obtained inExamples 6 and 7 exhibited considerably higher adhesion than thealuminum material of Conventional Example 2. Also in the case of forminga thicker carbon-containing layer, the aluminum materials coated withcarbon which were obtained in Examples 8 and 12 exhibited considerablyhigher adhesion than the aluminum material of Conventional Example 3. Inthis case, it is understood that the aluminum materials coated withcarbon in Examples 9 to 12 which were obtained by heat-treating after,in addition to the carbon-containing substance, an aluminum powder wasadhered to the foil exhibited higher adhesion than the aluminum materialcoated with carbon in Example 8 which was obtained by heat-treatingafter only the carbon-containing substance was adhered to the foil.

The aluminum material coated with carbon which was obtained in ReferenceExample 1 by carrying out heat treatment in an atmosphere of argon gaswhich was inert gas used in place of the atmospheric gases containingthe hydrocarbon-containing substance (Examples 1 to 5) exhibited loweradhesion like the Conventional Example 1.

Though, in the above examples, the cases where a carbon-containingsubstance is adhered to the surface of an aluminum material, followed bycarrying out heat treatment are shown, it was confirmed that evensamples obtained when a carbon-containing substance is not adhered tothe surface of an aluminum material in advance exhibited higher adhesionthan those currently in use.

When the surface of the sample obtained in Example 5 was observed by ascanning electron microscope (SEM), the existence of a portion extendingoutward from the surface of the aluminum foil in a fibrous form or afilament form about 1000 nm in length as the carbon-containing layer wasconfirmed. A typical sectional view of Example 5 is shown in FIG. 2.Also, the presence of aluminum carbide was confirmed by X-ray analysisand an electron energy loss spectrometer (EELS).

When the surface of the sample obtained in Example 10 was observed by ascanning electron microscope (SEM), the existence of a carbon-containinglayer was confirmed, the carbon-containing layer being constituted of aportion extending outward in a cactus form from a large number ofparticle portions having a particle diameter of about 1 μm whichparticle portions are adhered onto the surface of the aluminum foil anda large number of particle portions having a particle diameter of about0.1 μM which particle portions are adhered onto the above portion. Thetypical sectional view of Example 10 is shown in FIG. 4. Also, thepresence of aluminum carbide was confirmed by X-ray analysis and anelectron energy loss spectrometer (EELS).

Reference Example 2

An aluminum foil having a thickness of 30 μm (JIS A1050-H18) was kept at590° C. for 10 hours in an argon gas atmosphere. After that, the surfaceof the sample was observed by a scanning electron microscope (SEM). As aresult, the existence of a portion extending outward from the surface ofthe aluminum foil in a fibrous form or a filament form was notconfirmed. Also, the presence of aluminum carbide was not confirmed byX-ray analysis and an electron energy loss spectrometer (EELS).

Example 13

An aluminum foil having a thickness of 30 μm (JIS A1050-H18) was kept at590° C. for 10 hours in an acetylene gas atmosphere. Thereafter, thesurface of the sample was observed by a scanning electron microscope(SEM), to confirm the existence of a portion extending outward from thesurface of the aluminum foil in a fibrous form or a filament form about1000 nm in length as the carbon-containing layer. FIG. 1 is a typicalsectional view of the above portion. Also, the presence of aluminumcarbide was confirmed by X-ray analysis and an electron energy lossspectrometer (EELS).

Reference Example 3

An aluminum material having a thickness of 40 μm (JIS A1080-H18) wassubjected to a.c. etching treatment carried out in an electrolyticsolution containing 15% of hydrochloric acid and 0.5% of sulfuric acidin the condition of a temperature of 50° C. and a current density of 0.4A/cm² for 60 seconds and then, the etched aluminum material was washedwith water and dried.

Reference Example 4

The etched aluminum material obtained in Reference Example 3 was kept at590° C. for 10 hours in an argon gas atmosphere.

Example 14

The etched aluminum material obtained in Reference Example 3 was kept at590° C. for 10 hours in an acetylene gas atmosphere.

Example 15

2 Parts by weight of carbon black having an average particle diameter of0.5 μm was mixed with 1 part by weight of a binder containing at leastcarbon and hydrogen and the mixture was dispersed in a solvent (toluene)to obtain a coating solution having a solid content of 30%. This coatingsolution was applied to both surfaces of an aluminum material having athickness of 30 μm (JIS A1050-H18) and dried. The dry thickness of thecoating layer formed on one surface was 1 μm. This aluminum material waskept at 590° C. for 10 hours in a methane gas atmosphere. Then, when thesurface of the sample was observed by a scanning electron microscope(SEM), the existence of a carbon-containing layer was confirmed, thecarbon-containing layer being constituted of a portion extending outwardin a fibrous form or a filament form about 1000 nm in length from thesurface of the aluminum material and a large number of particle portionshaving a particle diameter of about 0.5 μm which particle portions areadhered to the above extended portion. The typical sectional view ofthis carbon-containing layer is shown in FIG. 2. Also, the presence ofaluminum carbide was confirmed by X-ray analysis and an electron energyloss spectrometer (EELS).

Example 16

2 Parts by weight of an aluminum powder having an average particlediameter of 1 μm was mixed with 1 part by weight of a binder containingat least carbon and hydrogen and the mixture was dispersed in a solvent(toluene) to obtain a coating solution containing a solid content of30%. This coating solution was applied to both surfaces of an aluminummaterial having a thickness of 15 μm (JIS 1N30-H18) and dried. The drythickness of the coating layer formed on one surface was 2 μm. Thisaluminum material was kept at 620° C. for 10 hours in a methane gasatmosphere. Then, when the surface of the sample was observed by ascanning electron microscope (SEM), the existence of a portion extendingoutward in a cactus form about 5000 nm in length from a large number ofparticle portions having a particle diameter of about 1 μm whichparticle portions were adhered to the aluminum material as acarbon-containing layer was confirmed. The typical sectional view ofthis carbon-containing layer is shown in FIG. 3. Also, the presence ofaluminum carbide was confirmed by X-ray analysis and an electron energyloss spectrometer (EELS).

Examples 17 to 23

2 Parts by weight of carbon black having an average particle diameter of0.1 μm and 2 parts by weight of an aluminum powder having an averageparticle diameter of 1 μm were mixed with 1 part by weight of a bindercontaining at least carbon and hydrogen and the mixture was dispersed ina solvent (toluene) to obtain a coating solution having a solid contentof 30%. This coating solution was applied to both surfaces of analuminum material having a thickness of 1.5 mm (JIS A3003-H18) anddried. The dry thickness of the coating layer formed on one surface was4 μm. This aluminum material was subjected to heat treatment in theconditions shown in Table 2. In Example 21, the aluminum material wasrolled using a rolling mill at a reduction ratio of about 30% after theheat treatment. In Example 23, the aluminum material was subjected toactivating treatment carried out at 300° C. for 2 hours in air after theheat treatment. Then, when the surface of the sample was observed by ascanning electron microscope (SEM), the existence of a carbon-containinglayer was confirmed, the carbon-containing layer being constituted of aportion extending outward in a cactus form from a large number ofparticle portions having a particle diameter of about 1 μm and adheredonto the surface of the aluminum material and a large number of particleportions having a particle diameter of about 0.1 μm which particleportions are adhered onto the above extended portion. The typicalsectional view of this carbon-containing layer is shown in FIG. 4. TABLE2 Temperature Time Atmosphere (° C.) (Hr) Example 17 Acetylene gas 44060 Example 18 Acetylene-hydrogen mixed gas 490 10 Example 19 Methane gas540 10 Example 20 Methane-hydrogen mixed gas 590 10 Example 21Methane-argon mixed gas 590 10 Example 22 Methane gas 640 10 Example 23Methane gas 540 10

With respect to the aluminum materials coated with carbon which wereobtained in Examples 13 and 14 and the aluminum materials obtained inReference Examples 2 to 4, evaluation was made for the surfaceresistance characteristics. The evaluation conditions are as shownbelow. The evaluation results are shown in Table 3.

(Surface Resistance Characteristics)

The surface resistance characteristics were evaluated by an a.c.impedance method.

Each of the samples obtained in Examples 13 and 14 and ReferenceExamples 2 to 4 was dipped in an aqueous 1 M hydrochloric acid solutionkept at a temperature of 293 K to measure a.c. impedance under aconstant current. The impedance was measured at 20 frequencies rangingfrom 0.5 to 1000 Hz. Generally, the simplest equivalent circuit at theboundary of an electrode/aqueous solution is represented by a circuit inwhich a solution resistance is connected in series to a parallel circuitof a charge transfer resistance and an electric double layer capacitor.In light of this, the a.c. impedances measured in this condition wereexpressed as vectors on a complex plane where the X axis was a real partand the Y axis was an imaginary part. Also, the value at the point ofintersection with the X axis was found from the locus of a.c. impedanceof each sample to adopt it as surface resistance. TABLE 3 Surfaceresistance (Ω) Example 13 36 Reference Example 2 947 Example 14 27Reference Example 3 59 Reference Example 4 214

As is clear from the results of Table 3, the aluminum material coatedwith carbon which was obtained in Example 13 exhibited considerablylower surface resistance characteristics than the aluminum material ofReference Example 2. Also in the case of an aluminum material whosesurface had been etched, the aluminum coated with carbon which wasobtained in Example 14 exhibited considerably lower surface resistancecharacteristics than the aluminum material of Reference Example 3 or 4.

With respect to the aluminum materials coated with carbon which wereobtained in Examples 13 to 23 and the aluminum materials obtained inReference Examples 2 to 4, evaluation was made for the surface area. Theevaluation conditions are as shown below. The evaluation results areshown in Table 4.

(Surface Area)

The surface area was evaluated by means of capacitance. The capacitancewas measured in an aqueous ammonium borate solution (8 g/L) by a LCRmeter. TABLE 4 Capacitance (μF/cm²) Example 13 50 Reference Example 2 4Example 14 70 Reference Example 3 30 Reference Example 4 30 Example 15160 Example 16 480 Example 17 500 Example 18 510 Example 19 700 Example20 680 Example 21 600 Example 22 980 Example 23 2000

As is clear from the results shown in Table 4, the aluminum materialcoated with carbon which was obtained in Example 13 exhibited aconsiderably higher capacitance, namely, a considerably higher surfacearea, than the aluminum material of Reference Example 2. Also in thecase of an aluminum material whose surface was etched, the aluminummaterial coated with carbon which was obtained in Example 14 exhibited aconsiderably larger surface area than the aluminum materials ofReference Examples 3 and 4. Furthermore, the aluminum materials coatedwith carbon which were obtained in Examples 15 to 21 exhibited aconsiderably larger surface area than the aluminum material of ReferenceExamples 3 and 4 whose surface was etched.

The above disclosed embodiments and examples are illustrative in allpoints and are not to be considered to be restrictive. The scope of thepresent invention is defined by the appended claims rather than by theabove embodiments and examples and all variations and modificationswithin the scope of the claims and within the meaning of equivalence areinvolved.

INDUSTRIAL APPLICABILITY

The charging/discharging characteristics, capacity and life of a batteryor a capacitor can be improved by constituting an electrode structureusing an aluminum material coated with carbon according to thisinvention.

1. An aluminum material coated with carbon, comprising: an aluminummaterial (1); and a carbon-containing layer (2) formed on a surface ofsaid aluminum material (1), the aluminum material further comprising: aninterposition layer (3) that is formed between said aluminum material(1) and said carbon-containing layer (2) and contains an aluminumelement and a carbon element.
 2. The aluminum material coated withcarbon according to claim 1, wherein said carbon-containing layer (2)includes therein an interposition material (21) containing an aluminumelement and a carbon element.
 3. The aluminum material coated withcarbon according to claim 2, wherein said interposition material (21) isa compound of an aluminum element and a carbon element.
 4. The aluminummaterial coated with carbon according to claim 1, wherein saidcarbon-containing layer (2) is a compound of an aluminum element and acarbon element.
 5. The aluminum material coated with carbon according toclaim 1, wherein said carbon-containing layer (2) is formed so as toextend outward from the surface of said aluminum material (1).
 6. Thealuminum material coated with carbon according to claim 1, wherein saidinterposition layer (3) includes a first surface portion (3) that isformed on at least a part of the surface of said aluminum material (1)and contains a carbide of aluminum, and said carbon-containing layer (2)includes a second surface portion (21) that is formed so as to extendoutward from said first surface portion (3).
 7. The aluminum materialcoated with carbon according to claim 6, wherein said carbon-containinglayer (2) further includes carbon particles (22), and said secondsurface portion (21) is formed between said first surface portion (3)and said carbon particles (22) and contains a carbide of aluminum. 8.The aluminum material coated with carbon according to claim 7, whereinsaid carbon-containing layer (2) further includes aluminum particles(23), an aluminum particle surface portion (24) that is formed on atleast a part of the surface of said aluminum particles (23) and containsa carbide of aluminum, and an aluminum particle outside portion (25)that is formed so as to extend outward the surface of said aluminumparticles (23) from the aluminum particle surface portion (24) andcontains a carbide of aluminum.
 9. The aluminum material coated withcarbon according to claim 6, wherein said carbon-containing layer (2)further includes aluminum particles (23), an aluminum particle surfaceportion (24) that is formed on at least a part of the surface of saidaluminum particles (23) and contains a carbide of aluminum, and analuminum particle outside portion (25) that is formed so as to extendoutward the surface of said aluminum particles (23) from the aluminumparticle surface portion (24) and contains a carbide of aluminum, andsaid second surface portion (21) is formed between said first surfaceportion (3) and said aluminum particles (23) and contains a carbide ofaluminum.
 10. The aluminum material coated with carbon according toclaim 1, wherein a ratio of in thickness of said carbon-containing layer(2) is within a range between 0.1 or more and 1000 or less with respectto a thickness of said aluminum material (1).
 11. The aluminum materialcoated with carbon according to claim 1, which is used to constitute anelectrode structure.
 12. The aluminum material coated with carbonaccording to claim 11, wherein said electrode structure is any oneselected from the group consisting of an electrode and an electrodecurrent collector.
 13. The aluminum material coated with carbonaccording to claim 11, wherein said electrode structure is used toconstitute a capacitor.
 14. The aluminum material coated with carbonaccording to claim 13, wherein said capacitor is any one selected froman electrochemical capacitor and an electrolytic capacitor.
 15. Thealuminum material coated with carbon according to claim 11, wherein saidelectrode structure is used to constitute a battery.
 16. A manufacturingmethod of an aluminum material coated with carbon, comprising the stepsof arranging an aluminum material in a space containing ahydrocarbon-containing substance; and heating in the state where thealuminum material is arranged in the space containing thehydrocarbon-containing substance.
 17. The manufacturing method of analuminum material coated with carbon according to claim 16, furthercomprising the step of cooling and reheating the aluminum material aftersaid step of heating in the state where the aluminum material isarranged in the space containing the hydrocarbon-containing substance.18. The manufacturing method of an aluminum material coated with carbonaccording to claim 17, wherein said step of cooling and reheating thealuminum material is carried out within a temperature range between 100°C. or more and less than 660° C.
 19. The manufacturing method of analuminum material coated with carbon according to claim 16, wherein saidstep of arranging the aluminum material in the space containing thehydrocarbon-containing substance involves adhering at least one kindselected from the group consisting of a carbon-containing substance andan aluminum powder to the surface of the aluminum material and, then,arranging the aluminum material in the space containing thehydrocarbon-containing substance.
 20. The manufacturing method of analuminum material coated with carbon according to claim 16, wherein saidstep of heating in the state where the aluminum material is arranged inthe space containing the hydrocarbon-containing substance is carried outwithin a temperature range between 450° C. or more and less than 660° C.21. The manufacturing method of an aluminum material coated with carbonaccording to claim 16, wherein said step of arranging the aluminummaterial in the space containing the hydrocarbon-containing substanceinvolves arranging the aluminum material in a space containing aparaffin-type hydrocarbon.
 22. The manufacturing method of an aluminummaterial coated with carbon according to claim 16, wherein said step ofarranging the aluminum material in the space containing thehydrocarbon-containing substance involves arranging the aluminummaterial in a space containing methane.